DAKAR, Senegal — The news from Nigeria sounded almost too good to be true — and so it appears to have been.

Two weeks ago, Nigeria’s chief of defense staff, the country’s top military official, announced that a cease-fire had been reached with the militant Islamist group Boko Haram, while another ranking government official spoke of an imminent deal to release the abducted schoolgirls whose fate has riveted the world.

Alarm bells should have gone off immediately: Boko Haram’s leader had nothing to say about the supposed cease-fire; the government’s official spokesman was equally mute; and previous such official declarations had proved hollow.

Such appears to be the case this time as well. The leader of Boko Haram, Abubakar Shekau, appeared in a videotaped message released on Friday, according to Nigerian news accounts, dismissing any notion of a cease-fire and saying that the more than 200 schoolgirls kidnapped by his group last spring had been married off.

“All of them have accepted Islam and are now married,” he was quoted as saying. “Anybody that said plans are underway for the release of the girls is just daydreaming. They would not be returned.”

In the message, Mr. Shekau also said no cease-fire had ever been reached. “Who agreed to a cease-fire? You are not serious,” he was quoted as saying, adding that his continuing campaign in the region proved otherwise.

Since the cease-fire announcement, attacks and abductions have continued in the Boko Haram heartland in Nigeria’s northeast. At least 60 young women were reported to be kidnapped by militants in Adamawa State, just south of the Boko Haram stronghold near Maiduguri.

Residents and a Roman Catholic bishop said the latest kidnapping occurred the day after the announcement of the cease-fire, in an ominous repeat of the episode last April when more than 200 girls were abducted from a rural school in the region.

There have also been numerous attacks attributed to the militants, including one in a village north of Maiduguri this week in which several were killed and a market and a police station burned. On Wednesday, yet another lethal attack was reported, this time on the town of Mubi near the Cameroon border.

Nigerian officials have insisted that negotiations are still going on, though they have released no details of these discussions.

Soon after the government’s declarations of a cease-fire, President Goodluck Jonathan — who has been roundly criticized for failing to stop Boko Haram or to get the girls back safely — announced that he would indeed run for the presidency again in next year’s election. Any perceived progress on an issue in which there has been dismally little progress could be seen as a boost to the incumbent.

Meanwhile, the girls remain missing, Boko Haram still controls swaths of territory in the northeast around the Cameroon border, and villagers continue to be kidnapped and killed by the militants.

The one positive development for the government is that an imminent threat to the city of Maiduguri early in September — the Islamists were approaching it from three sides — appears to have been halted, for now, by a bombing campaign initiated by the Nigerian military.

This uneasy status quo does not threaten Mr. Jonathan’s re-election prospects. Already hated in the north of Nigeria, he had little chance of winning that region in any case.

In the heavily populated south and west, by contrast, Boko Haram is perceived as an almost foreign phenomenon — not something that affects the average resident of Lagos, the commercial capital. Whether Mr. Jonathan is winning or losing the war against the militants is considered to be of secondary importance to many there. He remains at the top of the governing People’s Democratic Party, an immense patronage machine — a critical variable in Nigeria’s political system.

The kidnappings in the north will likely continue, many warn. A report released this week by Human Rights Watch noted that the more than 200 schoolgirls abducted in April were hardly the first. The rights group estimated that at least 500 women and girls have been abducted by the militants since their insurgency began in 2009.

It detailed a litany of abuses to which these women have been subjected by the militants, based on accounts from those who have managed to escape.

The women have been forced to “marry,” cook and do menial chores for the militants in their camps in the forest, and convert to Islam; they have also been raped, beaten and threatened with death. The few schoolgirls who escaped in April told similar stories of brutal mistreatment. The Boko Haram leader, Mr. Shekau, has referred to these women as “slaves.”

Marc-Antoine Pérouse de Montclos, a French scholar and Boko Haram specialist, pointed out that the area that was now the group’s stronghold, the Mandara Mountains in Adamawa State, has also historically been a raiding ground for slaves by marauding Muslim Fulani warlords.

“Domestic slaves were used as currency, like cattle, or as a way to extract ransom and settle disputes,” Mr. Pérouse de Montclos wrote in a report this year for Chatham House, a London-based research group.

If anything, the abduction of the schoolgirls “appears to have emboldened Boko Haram to step up abductions elsewhere,” Human Rights Watch reported, noting a spate of abductions immediately after the one that grabbed the world’s attention.

A version of this article appears in print on , on Page A9 of the New York edition with the headline: In Nigeria, Fragile Hopes of Boko Haram Freeing Schoolgirls Are Dashed. Order Reprints | Today’s Paper | Subscribe